1. Field of the Invention
The invention relates to a method for producing a getter device, wherein a getter material is introduced into a container and the getter material is heated to a temperature under reduced pressure so that getter material is deposited on an inside of the container.
2. Discussion of Background Information
Getter devices are used, for example, in evacuated devices in which in operation or in use a vacuum is to be maintained over long periods as well as possible and therefore any gases entering have to be permanently bound by a getter material.
A getter material that has a high specific getter capacity for a specific gas, e.g., hydrogen, can be supplied in a tubular container of steel, wherein the container is closed at least at one end with a metal melting at low temperatures or a like alloy and the getter material is deposited in layers on an inside of the container.
In the production of a getter device of the above-mentioned type, the procedure has hitherto been that a getter material as a whole piece or powder is introduced into a vial, e.g., as mentioned of steel, closed on one side with a low-melting metal or a like alloy, after which the vial is likewise closed at the other end, e.g., by welding, under reduced pressure, that is, a pressure of less than 1 bar, preferably (high) vacuum. Subsequently, the enclosed getter material is heated so that the getter material in part evaporates and is deposited at a cool point of an inside of the vial in the form of layers. The getter material is thereby intended to be distributed over a large area, which is available later for binding undesirable gases. After an installation in a device and evacuation of the device, the getter device is heated at least in the region of the metal or the corresponding alloy forming a closure and opened thereby so that gases to be bound penetrate into the interior of the getter device and can be bound to the getter material deposited in layers.
In the approach according to the prior art, it has proven to be a disadvantage that only such a limited amount of getter material can be introduced into the vial, that the inside of a container is just covered during the deposition of getter material. If too much getter material is introduced, a plug easily forms or the vial is closed up during the subsequent deposition of the same at a cool point of the vial, so that ultimately a high getter capacity desired for uses is not achieved.